ESP8266 Community Forum

- Wed Jun 09, 2021 11:30 am #91593 Hello, I am facing problems to use espnow and Exchange data between two ESP8266.
Already tried with two ESP32 and had the same problem, which is I am able to send data ( a text message) but it fails to be delivered.
Probably it is a silly detail but I am stuck and do not know what to do next. Find below master and slave codes.
Any help or advice would be greatly appreciated.
MASTER:
#include <ESP8266WiFi.h>
extern "C" {
#include <espnow.h>
}
// This is the slave MAC Address which receives the data
// uint8_t mac[] = {0x48, 0x3F, 0xDA, 0x7E, 0x30, 0xF8}; //AP MAC MASTER'S ADDRESS
uint8_t mac[] = {0x48, 0x3F, 0xDA, 0x7E, 0x5A, 0xCA}; //AP MAC SLAVE'S ADDRESS

#define WIFI_CHANNEL 4
int prevstate_1 = LOW;
int prevstate_2 = LOW;

// Data structure, must be the same for the slave

struct __attribute__((packed))DataStruct {
char text[32];
};
DataStruct button_1;
DataStruct button_2;

// Callback when data is sent
void OnDataSent(uint8_t *mac, uint8_t sendStatus) {
Serial.print("Last Packet Send Status: ");
if (sendStatus == 0){
Serial.println("Delivery success");
}
else{
Serial.println("Delivery fail");
}
}

//=====================================================================================================
void setup() {
pinMode(D1, INPUT_PULLUP);
pinMode(D4, INPUT_PULLUP);
pinMode(D2, OUTPUT);
pinMode(D3, OUTPUT);

Serial.begin(115200); Serial.println();
Serial.println("Starting EspnowController.ino");
WiFi.mode(WIFI_STA); // Station mode for esp-now controller
WiFi.disconnect();
Serial.printf("This mac: %s, ", WiFi.macAddress().c_str());
Serial.printf("slave mac: %02X%02X%02X%02X%02X%02X", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
Serial.printf(", channel: %i\n", WIFI_CHANNEL);
if (esp_now_init() != 0)
{
Serial.println("*** ESP_Now initialization failed");
}
esp_now_set_self_role(ESP_NOW_ROLE_CONTROLLER);
esp_now_add_peer(mac, ESP_NOW_ROLE_SLAVE, WIFI_CHANNEL, NULL, 0);
strcpy(button_1.text, "Button 01 pressed");
strcpy(button_2.text, "Button 02 pressed");
Serial.println("Setup finished");
// Once ESPNow is successfully Init, we will register for Send CB to
// get the status of Trasnmitted packet
esp_now_register_send_cb(OnDataSent);
}

//======================================================================================================

void loop() {
sendData();
}

//======================================================================================================
void sendData() {

int currentstate_1 = digitalRead(D4);
if (prevstate_1 != currentstate_1) {
if (currentstate_1 == LOW) {
uint8_t bs[sizeof(button_1)];
memcpy(bs, &button_1, sizeof(button_1));
esp_now_send(mac, bs, sizeof(button_1));
Serial.println(button_1.text);
digitalWrite(D2, !digitalRead(D2));
}
} prevstate_1 = currentstate_1;

int currentstate_2 = digitalRead(D1);
if (prevstate_2 != currentstate_2) {
if (currentstate_2 == LOW) {
uint8_t bs[sizeof(button_2)];
memcpy(bs, &button_2, sizeof(button_2));
esp_now_send(mac, bs, sizeof(button_2));
Serial.println(button_2.text);
digitalWrite(D3, !digitalRead(D3));
}
} prevstate_2 = currentstate_2;
}
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
SLAVE


#include <ESP8266WiFi.h>
extern "C" {
#include <espnow.h>
#include <user_interface.h>
}
uint8_t mac[] = {0x48, 0x3F, 0xDA, 0x7E, 0x30, 0xF8}; //AP MAC SLAVE'S ADDRESS

//============================================================================================

int Led1 = D0;
int Led2 = D1;

void initVariant() {
WiFi.mode(WIFI_AP);
wifi_set_macaddr(SOFTAP_IF, &mac[0]);
}

//=============================================================================================
#define WIFI_CHANNEL 4

// must match the controller struct
struct __attribute__((packed))DataStruct {
char text[32];
unsigned int time;};

DataStruct receivedData;

//=============================================================================================
void setup() {
Serial.begin(115200); Serial.println();
Serial.println("Starting EspnowSlave.ino");

Serial.print("This node AP mac: "); Serial.println(WiFi.softAPmacAddress());
Serial.print("This node STA mac: "); Serial.println(WiFi.macAddress());
Serial.printf(", channel: %i\n", WIFI_CHANNEL);
pinMode(Led1,OUTPUT);
pinMode(Led2,OUTPUT);

if (esp_now_init() != 0) {
Serial.println("*** ESP_Now init failed");
while (true) {};
}

esp_now_set_self_role(ESP_NOW_ROLE_SLAVE);
esp_now_register_recv_cb(receiveCallBackFunction);
Serial.println("End of setup - waiting for messages");
}

//==============================================================================================

void loop() {
}

//==============================================================================================
//void receiveCallBackFunction(uint8_t *senderMac, uint8_t *incomingData, uint8_t len) {
void receiveCallBackFunction(uint8_t *mac, uint8_t *incomingData, uint8_t len) {

Serial.print("INCOMING=");
Serial.println(*incomingData);

Serial.print("len=");
Serial.println(len);
memcpy(&receivedData, incomingData, sizeof(receivedData));

// Serial.print("INCOMING_AFTER=");
//Serial.println(incomingData);

Serial.print("len_AFTER=");
Serial.println(receivedData.text);

String DataCompare = String(receivedData.text);

if(DataCompare == "Button 01 pressed"){
digitalWrite(Led1, !digitalRead(Led1));
Serial.println(" Message = " + DataCompare);
}
if(DataCompare == "Button 02 pressed"){
digitalWrite(Led2, !digitalRead(Led2));
Serial.println(" Message = " + DataCompare);

}

- Thu Jun 24, 2021 1:45 am #91752 You should first reduce the code and just try the basic communication first. Moreover, add formatted code as it's too difficult to read it. Use code tags.